Acceleration responsive switch with magnetic actuator means

ABSTRACT

An acceleration responsive switching device which comprises a substantially generally cylindrical casing having formed a limited space over its upper peripheral surface and a substantially vertical bore with its one end open extending at a slight distance from a central portion of the limited space, acceleration sensing means accommodated in the limited space, a switch actuating means accommodated in the vertical bore and a switch element provided downwardly of the open end of the vertical bore. The acceleration sensing and switch actuating means are composed of a permanent magnet and a magnet substance, respectively, and vice versa. With this arrangement, the acceleration responsive switching device is actuated by an acceleration exceeding a predetermined level encountered in such moving vehicle as an automobile.

United States Patent m1 Suzuki July 24, 1973 [54] ACCELERATIONRESPONSIVE SWITCH 3,379,059 4/1968 Wiley ZOO/61.45 M ux WITH MAGNETICACTUATOR MEANS 3,397,372

Inventor: Masaru Suzuki, l-lekikai, Japan Kabushiki Kaisha Tokai RikaDenki Seisakusho, Nishikasugai-gun, Japan Filed: Nov. 26, 1971 Appl.No.: 202,310

Assignee:

Foreign Application Priority Data Nov. 28, 1970 Japan..... 45/118184(utility model) 8/1959 Clurman ..200/6l.45M 6/1967 Maxwell ..335/2058/1968 Maxwell ..335/205 Primary Examiner-J. R. Scott Attorney-Woodhams,Blanchard and Flynn [57] ABSTRACT An acceleration responsive switchingdevice which comprises a substantially generally cylindrical casinghaving formed a limited space over its upper peripheral surface and asubstantially vertical bore with its one end open extending at a slightdistance from a central portion of the limited space, accelerationsensing means accommodated in the limited space, a switch actuatingmeans accommodated in the vertical bore and a switch element provideddownwardly of the open end of the vertical bore. The accelerationsensing and switch actuating means are composed of a permanent magnetand a magnet substance, respectively, and vice versa. With thisarrangement, the acceleration responsive switching device is actuated byan acceleration exceeding a predetermined level encountered in suchmoving vehicle as an automobile.

5 Claims, 2 Drawing Figures PAINTED- FIG.1

INVENTOR MAS/mu SuzuK/ BY WW flue/Mm ATTORNEY ACCELERATION RESPONSIVESWITCH WITH MAGNETIC ACTUATOR MEANS This invention generally relates toa switching device and, more particularly, to an acceleration responsiveswitching device which is adapted to be actuated in response to anacceleration exceeding a predetermined level encountered in accordancewith a driving condition of a moving vehicle such as an automobile.

It is an object of the present invention to provide an improvedacceleration responsive switching device for use in a moving vehiclesuch as an automobile.

Another object of the present invention is to provide an accelerationresponsive switching device which is operable notwithstanding shocks andimpacts and, particularly, vibrations which are all apt to be appliedcontinuously thereto while driving.

The acceleration responsive switching device to achieve these object isbasically made up of a substantially generally cylindrical casing havingformed a limited space over its upper peripheral surface and asubstantially vertical bore with its one end open extending at a slightdistance from a central portion of the limited space, accelerationsensing means accommodated in the limitted space, a switch actuatingmeans accommodated in the vertical bore and a switch element provideddownwardly of the open end of the vertical bore. lt is an importantfactor here in the present invention that the acceleration sensing andswitch actuating means are composed of a permanent magnet and a magnetsubstance, respectively, and vice versa and, under an inoperativecondition of the device, juxtaposed with each other with a relativelythin partition interposed therebetween.

These and other objects and advantages of the pres ent invention will bemore clearly appreciated from the following description taken inconjunction with the accompanying drawings in which:

FlGnl is a vertical sectional view showing a preferred example of theacceleration responsive switching device embodying the presentinvention; and

FIG. 2 is a vertical section of another preferred example of the deviceaccording to the present invention.

Referring to FlG. 1, there is shown a preferred example of theacceleration responsive switching device according to the presentinvention, which device comprises a substantially generally cylindricalcasing designated by reference numeral 1. The casing has formed itsupper peripheral surface a reverse conical end wall 2 having a lowest orcentral portion b. The reverse conical end'wall 2 of the casing 1defines thereupon a chamber a in combination with a cap member 4 whichis preferably threadedly fitted to the casing l, as is shown in thedrawing. An inner peripheral wall 5 of the cap member 4 is soconfigurated as to be equidistantly spaced from the vis-a-vis end wall 2throughout the total area, viz a conical shape corresponding to theshape of the end wall 2. The casing I has further formed therein asubstantially vertical bore 3 with its lower end (not numbered) open andextending at a slight distance from the central portion b of the endwall 2, thus defining a relatively thin partition.

Designated by reference numeral 6 is a switch element or a microswitchdisposed in a manner to close the open end of the vertical bore 3. Themicroswitch 6 has self-returning push button 7 which is normally forcedoutwardly by a spring force, the push button 7 facing the vertical bore3.

An acceleration sensing means or a weight ball 8 made of steel is snuglyaccommodated in the central portion b of the reverse conical end wall 2due to its gravitation under normal condition; that is, when theacceleration applied is maintained within the predetermined level inmagnitude. The weight ball 8 is capable of moving substantially in alldirections throughout the surface of the end wall 2.

It is to be noted here that the weight ball 8 is generally preventedfrom a vertical movement away from the reverse conical end wall 2because of the conical configuration of the inner peripheral wall 5 ofthe cap member 4.

A switch actuating means adapted to actuate the microswitch 6 iscomposed of a permanent magnet 9 hav ing magnet poles at upper and lowerends thereof. This permanent magnet 9 is accommodated in the verticalbore 3 so as to be juxtaposed with the weight ball normally stationed atthe central portion b of the end wall 2.

With this arrangement, while an acceleration is maintained within apredetermined level in magnitude, the weight ball 8 in the chamber a ispositioned stationarily at the central portion b, as has precedinglydescribed,

so that the permanent magnet 9 accommodated in the vertical bore 3attracts in this instance the weight ball 8 existing immediately in theabove. Since, however, the weight ball 8 is prevented from movingdownwardly into the bore 3 by the partition interposed therebetween, thepermanent magnet per se is urged upwardly and held in the uppermostportion of the vertical bore 3 in contact with an upper end wall (notnumbered) of the bore 3. Consequently, the push button 7 is keptdisengaged from the permanent magnet whereby the microswitch is actuatedin an operative or inoperative condition.

When, in operation, an acceleration exceeding a predetermined level iscaused to the acceleration responsive switching device, the accelerationis detected by the weight ball 8 which is moved through its inertia awayfrom the central portion b on the end wall 2 to, for example, a positionindicated by a phantom line in the drawing. In this instance, losing anobject for attraction, the permanent magnet 9 is urged downwardly in thebore 3 due to its gravity. The push button 7 then is brought intoengagement with the permanent magnet and is pressed thereby with theresult that the microswitch 6 is actuated.

FIG. 2 illustrates another preferred example of the accelerationresponsive switching device embodying the present invention, in whichthe weight ball made of steel and the permanent magnet used in thepreceding example are utilized as a switch actuating means and anacceleration sensing means, respectively, thus a modification beingapplied to the arrangement and structure of the device per se.

A substantially generally cylindrical casing designated by referencenumeral 11 has formed a relatively deep cavity 12 which is open at theupper end (not numbered) and has a concave configuration of its bottomend wall 13. Indicated by reference numeral c is a lowest or centralportion of the bottom end wall 12. The casing l 1 has further formed avertical bore 14 extending vertically with its lower end (not numbered)open and at a slight spacing from the central portion c of the bottomend wall 12, thus leaving a relatively thin partition between the cavity12 and the bore 14. A closure member 15 provided in a manner to closethe upper open end of the cavity 12 is secured to the casing 11 by a capmember 16 which is fitted to the casing 11 preferably through threads,as is shown in the drawing. Centrally of the upper peripheral surface ofthe closure member 15 is formed a ball bearing surface 17 as a bore inwhich seated a rotatable spherical member 18. A non-magnetic rod 19secured at one end to the spherical member 18 extends midway into thecavity 12, having secured at the other end thereof a permanent magnet 20functioning as an acceleration sensing means. The permanent magnet 20fitted to the lower end of the rod 19 has its magnetic poles at theupper and lower ends, of which lower end faces the bottom end wall 13 ofthe cavity 12 at a suitable distance therefrom.

Designated by reference numeral 21 is a switch element or a microswitchwhich closes the open lower end of the vertical bore 14 in the samemanner as has been illustrated in accordance with FIG. 1. Furthermore,the microswitch 21 has a self-returning push button 22 normally extrudedinto the bore 14. A weight ball 23 made of steel is movably accommodatedin the bore 14 as a switch actuating means, being supported by the pushbutton.

As will now be seen, the permanent magnet 20 supported by the rotatablespherical member 18 through the rod 19 is allowed to have a similarmovement to that of a bob fitted to a pendulum, but substantially in alldirections with the spherical member 18 as a fulcrum, lt is to beunderstood that the permanent magnet has a stationary position, underthe normal condition, corresponding to the lowest or central portion cof the bottom end wall 13. Furthermore, the weight ball 23 made of steelfunctioning as the switch actuating means is capable of moving in thevertical direction in the bore 14 but, on the other hand, restrained ofentering the cavity 12 by the partition provided therebetween.

Thus, under the inoperative condition of the device, the permanentmagnet 20 being positioned in the central portion over the bottom endwall of the cavity 12, the weight ball 23 is held in the uppermostportion of the vertical bore in contact with the upper end wall (notnumbered) thereof due to a magnet force of the lower magnet pole so thatthe permanent magnet is also held unmoved. Under this condition, thepush button 22 of the microswitch 21 is maintained its extended positionso as to keep the microswitch either operative or inoperative condition.

When, in turn, an acceleration exceeding a predtermined level inmagnitude is applied to the acceleration responsive switching deviceunder the above-described normal condition, the permanent magnet 20 ismoved by its inertia away from the stationary portion to, for example, aposition indicated by phantom line in the drawing. The weight ball 23released from the magnetic attraction is then urged downwardly due toits gravity with the result that the push button is depressed and,accordingly, the microswitch is actuated.

It is to be noted that an auxiliary support member may be provideddownwardly of the vertical bore formed in the casing for the purpose ofsupplying an additional support for the switch actuating means actuatingthe switch element, as such will be applied to both of the examplesshown in the present specification.

It will now be appreciated from the foregoing description that theacceleration responsive switching device according to the presentinvention is advantageous in that, since either one of the accelerationsensing means and the switch actuating means is composed of a permanentmagnet with the other made of magnetic substance and they are juxtaposedwith each other through a desirably thin partition providedtherebetween, the acceleration sensing and the switch actuating meansrestrain each other of unnecessary movements yet without being broughtinto direct contact with each other with the result that the former andthe latter are respectively prevented from dropping into the verticalbore and jumping into the chamber or cavity formed in the casing.Furthermore, the switching operation acording to the present inventionis performed through supporting the switch actuating means by the switchelement, so that, as a whole, the device of this invention is capable ofperforming its operation promptly and yet with high accuracynotwithstanding shocks and impacts and, particularly, vibrations appliedthereto under driving conditions of the moving vehicle.

What is claimed is:

1. An acceleration responsive switching device, comprising incombination:

a casing having a limited space over the upper peripheral surfacethereof, and a substantially vertical bore extending from a centralportion of said limited space and separated therefrom by a partition,said bore having an open lower end;

an acceleration sensing means normally located in the central portion ofsaid limited space and laterally displaceable therefrom in response to apredetermined magnitude of acceleration of said device;

a switch actuating means freely movable in said bore and normally heldat said partition by magnetic attraction between said accelerationsensing means and switch actuating means, one of said accelerationsensing means and switch actuating means comprising a permanent magnetand the other comprising a magnetically attractable member;

a switch element adjacent the open lower end of said bore and actuableby downward movement of said switch actuatingmeans theretoward resultingfrom said lateral displacement of said acceleration responsive meansfrom said central portion.

2. An acceleration responsive switching device according to claim 1,wherein said acceleration sensing means is a steel weight ball and saidswitch actuating means is a permanent magnet having magnet poles at theupper and lower ends thereof, said limited space accommodating saidweight ball comprises a chamber formed by a reverse conical upper endwall of said casing and a cap member, said cap member being configuratedin a conical shape corresponding to said reverse conical upper end wallof said casing and being fitted to said casing.

3. An acceleration responsive switching device according to claim 1,wherein said acceleration sensing means is a permanent magnet havingmagnet poles at upper and lower ends thereof and said switch actuatingmeans is a steel weight ball, said casing having a concave upper endwall, and further comprising a closure member fitted to the upper end ofsaid casing and defining said limited space as a relatively deep cavityin combination with said concave upper end wall of said casing, a capmember securing said closure member to said casing, said closure memberhaving a further bore formed centrally of its upper peripheral surfaceand defining a ball bearing surface, a rotatable spherical member seatedon said ball bearing surface and a nonmagnetic rod having one end fittedto said spherical member and the other end holding said permanent magnetand extending midway into said cavity.

4. An acceleration responsive switching device according to claim 1,wherein said switching element is a microswitch having a push buttonnormally held in an extended conditin through a spring force.

5. An acceleration responsive switching device acvice.

1. An acceleration responsive switching device, comprising incombination: a casing having a limited space over the upper peripheralsurface thereof, and a substantially vertical bore extending from acentral portion of said limited space and separated therefrom by apartition, said bore having an open lower end; an acceleration sensingmeans normally located in the central portion of said limited space andlaterally displaceable therefrom in response to a predeterminedmagnitude of acceleration of said device; a switch actuating meansfreely movable in said bore and normally held at said partition bymagnetic attraction between said acceleration sensing means and switchactuating means, one of said acceleration sensing means and switchactuating means comprising a permanent magnet and the other comprising amagnetically attractable member; a switch element adjacent the openlower end of said bore and actuable by downward movement of said switchactuating means theretoward resulting from said lateral displacement ofsaid acceleration responsive means from said central portion.
 2. Anacceleration responsive switching device according to claim 1, whereinsaid acceleration sensing means is a steel weight ball and said switchactuating means is a permanent magnet having magnet poles at the upperand lower ends thereof, said limited space accommodating said weightball comprises a chamber formed by a reverse conical upper end wall ofsaid casing and a cap member, said cap member being configurated in aconical shape corresponding to said reverse conical upper end wall ofsaid casing and being fitted to said casing.
 3. An accelerationresponsive switching device according to claim 1, wherein saidacceleration sensing means is a permanent magnet having magnet poles atupper and lower ends thereof and said switch actuating means is a steelweight ball, said casing having a concave upper end wall, and furthercomprising a closure member fitted to the upper end of said casing anddefining said limited space as a relatively deep cavity in combinationwith said concave upper end wall of said casing, a cap member securingsaid closure member to said casing, said closure member having a furtherbore formed centrally of its upper peripheral surface and defining aball bearing surface, a rotatable spherical member seated on said ballbearing surface and a non-magnetic rod having one end fitted to saidspherical member and the other end holding said permanent magnet andextending midway into said cavity.
 4. An acceleration responsiveswitching device according to claim 1, wherein said switching element isa microswitch having a push button normally held in an extended conditinthrough a spring force.
 5. An acceleration responsive switching deviceaccording to claim 1, in which said casing is substantially cylindricaland has a concave upper surface, means including a cap threaded to saidcasing and spaced above said upper surface to define said limited space,said bore being aligned between said central portion and said switchelement, said switch actuating means being longitudinally slidabLydisposed in said bore, whereby said magnetic attraction between saidacceleration sensing means and switch actuating means tends to hold theacceleration sensing means at said central portion in the normalunaccelerated condition of said device.